Capture the stage

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations exist, so the description carries the full disclosure burden. It usefully says the result includes a timestamp and an image block, but it says nothing about prerequisites (must a stage be open? does it change focus?), side effects, or any capture limits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tightly written sentences with the core action front-loaded and no filler. Nothing in it is wasted.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The return shape is partially covered, which matters since there is no output schema, but with zero annotation coverage and an undocumented nested parameter, an agent still lacks enough to invoke it confidently in edge cases like full_page.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% across three parameters, including a nested clip object. The description only hints at stage_id via 'current stage' and never explains the clip region or what full_page toggles (full document vs. viewport).

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: 'Take a PNG of the current stage', plus what it returns (an image block plus metadata). It is clear what the tool does, but it never names the neighboring tools (stage_state, measure, diff) it is meant to be distinguished from.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The clause 'it does not judge the frame' draws a scope boundary, implying evaluation belongs elsewhere, but neither the alternative tools nor the conditions for choosing them are stated. Usage is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.